Influence of solidification variables on the dendrite arm spacings of Ni-based superalloys
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NCuS 0.0462 0.0424 0.0395 0.0369 0.0346
( ps2)1/2-ZL 0.0285 0.0252 0.0228 0.0210 0.0196
( ps2)1/2-SM 0.1237 0.1061 0.0943 0.0848 0.0772
Mass Pct Pb 0.341 0.278 0.233 0.192 0.163
aPb 9.93 9.28 8.61 7.80 6.99
3 3 3 3 3
p (PbS) 24
10 1024 1024 1024 1024
19.9 16.4 13.8 11.5 9.6
3 3 3 3 3
p (Pb) 25
10 1025 1025 1025 1025
3.4 3.2 2.9 2.7 2.4
3 3 3 3 3
p (Pb2) 25
10 1025 1025 1025 1025
9.5 8.3 7.1 5.8 4.7
3 3 3 3 3
212
10 10212 10212 10212 10212
gPbS 0.298 0.303 0.304 0.307 0.303
Note: Recalculation of Zhong–Lynch’s experiments[4]; Ns refers to the atomic fraction of sulfur in the Cu-S-Pb melts; NCuS refers to the mole fraction of CuS in the CuS0.5-CuS-PbS system matte; ( ps2)1/2-ZL is the square root of S2 partial pressure from Zhong and Lynch[4]; ( ps2)1/2-SM is the square root of S2 partial pressure from Schuhmann and Moles;[15] and p (i) refers to the partial pressure (in atm) of gaseous species i over molten matte at 1533 K.
Influence of Solidification Variables on the Dendrite Arm Spacings of Ni-Based Superalloys H.S. WHITESELL, L. LI, and R.A. OVERFELT The primary (l1) and secondary (l2) dendrite arm spacings are key microstructural features of directionally solidified castings since they influence many of the important mechanical properties. For any given alloy, the spacings are controlled by the thermal gradient, G, and the solidification velocity, V, as well as any potential effects of convection. Bouse and Mihalisin[1] reviewed the literature and summarized the effect of cooling rate (GV ) on l1 and l2 for eight different nickel-based superalloys. Hunt[2] and Kurz and Fisher[3] have shown that primary dendritic spacings in binary alloy systems under steady-state growth can be characterized by
l1 5 KGaV b
Fig. 2—Raoultian activity coefficients (g) of Bi (l), BiS (l), and BiS1.5 (l) in the CuS0.5-Cu(-CuS)-Bi, CuS0.5-Cu(-CuS)-BiS, or CuS0.5-Cu(-CuS)BiS1.5 system matte. The term Ns refers to the atomic fraction of sulfur in the Cu-S-Bi melt. Data points are from RJ,[3] except for the Cu-saturated mattes attributed to NEMP.[8]
5. R.W. Ruddle, B. Taylor, and A.P. Bates: Trans. Inst. Mining Metall., 1966, vol. 75C, pp. 1-12. 6. E.T. Turkdogan: Physicochemical Properties of Molten Slags and Glasses, The Metals Society, London, 1983, pp. 309-17. 7. A. Yazawa, S. Nakazawa, and Y. Takeda: in Advances in Sulfide Smelting, vol. 1, Basic Principles, H.Y. Sohn, D. B. George, and A.D. Zunkel, eds., TMS, Warrendale, PA, 1983, pp. 99-117. 8. M. Nagamori, W.J. Errington, P.J. Mackey, and D. Poggi: Metall. Mater. Trans. B, 1994, vol. 25B, pp. 839-53. 9. C.W. Bale and J.M. Toguri: J. Thermal Anal., 1971, vol. 3, pp. 153-67. 10. O. Kubaschewski and C.B. Alcock: Metallurgical Thermochemistry, Pergamon Press, New York, NY, 1979, pp. 360 and 368. 11. I. Barin: Thermochemical Data of Pure Substances, VCH, Weinheim, 1989, pp. 1127 and 1129. 12. P.C. Chaubal and M. Nagamori: Metall. Trans. B, 1988, vol. 19B, pp. 547-56. 13. E.T. Turkdogan: Physical Chemistry of High Temperature Technology, Academic Press, New York
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